1. Field of the Invention
This invention pertains to self-propelled upright vacuum cleaners. More specifically, this invention pertains to a novel linkage mechanism for automatically preventing engagement of the transmission on a self-propelled upright vacuum cleaner when the handle or upper housing portion of the cleaner is placed in its upright storage position.
2. Description of Related Prior Art
It is known in the prior art to provide an upright vacuum cleaner with a transmission in the foot or lower floor engaging portion of the cleaner and a transmission actuator member mounted to the foot adjacent to the transmission. A Bowden cable typically extends from the actuator on the foot to a hand grip that is reciprocally mounted for rectilinear motion to the top of the housing or handle portion of the cleaner.
Prevention of accidental engagement of the transmission when the housing is in the upright storage position is a problem that has been addressed in the art. For example, it is known to provide a member on the lower end of the housing or handle portion of the vacuum cleaner that will engage the transmission actuator, or actuate a member on the foot that engages the transmission actuator, and thereby place and lock the transmission actuator in its neutral position. Thus, if an operator were to accidentally bump the hand grip while the cleaner's housing is in the upright storage position and the motor is running, the transmission is prevented from being engaged and the cleaner is prevented from accidentally propelling itself across the floor. Such transmission neutral locking arrangements for self-propelled upright vacuum cleaners are disclosed in U.S. Pat. Nos. 4,766,640; 4,347,643; and 4,249,281.
It is also known to position the transmission actuator relative to the lower end of the housing such that a member carried on the housing directly contacts the actuator to selectively engage the transmission when the housing is in its inclined operating position and is prevented from contacting the actuator when the housing is in its upright storage position. When the transmission is not being engaged by the actuator, the transmission is self-biased into an idling neutral position. An example of this type of self-propelled vacuum cleaner can be found in U.S. Pat. No. 3,618,687.
Further, U.S. Pat. No. 5,974,622 discloses a self-propelled upright vacuum cleaner having a lower portion and an upright handle pivotally attached to the floor engaging portion for a pivotal motion between an upright storage position and a pivotal operating position. First and second cams extend from the handle portion and are located to engage the actuator arm at two locations spaced to either side of the pivot axis of the actuator arm when the handle is raised to the upright storage position, whereby the cams place and lock the actuator arm in the neutral position when the handle portion is pivoted to the upright storage position.
The present invention utilizes a novel mechanical linking mechanism to actuate the transmission to place the transmission in forward, reverse or neutral when the handle is in an inclined, operative position. When the handle is in a upright storage position, the linkage is inoperable, thereby preventing the cleaner from being inadvertently propelled along the floor.
It is therefore an object of the present invention to provide an improved linking mechanism to actuate the transmission of a self-propelled upright vacuum cleaner wherein the linkage mechanism between the handle portion and the clutch engaging device is operational only when the housing and handle portion are in an inclined position and is inoperable when the assembly and handle portion of the vacuum cleaner is in a fully upright position.
It is a further object of the present invention to provide a method for actuating the transmission of a self-propelled upright vacuum cleaner when the assembly and handle of the vacuum cleaner is in an inclined, operative position, and disengaging the transmission of the vacuum cleaner when the assembly and handle of the vacuum cleaner is in a fully upright position.